kurtm Posted February 4, 2015 Share Posted February 4, 2015 No fix, just don't buy one that jams tight to the upper receiver. Ive seen several now that have a continuous top rail that is designed to fit tightly to the upper receiver rail, also there are a few that the handguard is jammed into the upper right at the junction where the gas tube goes through. Bad design for accuracy. A good free float has at least .005 clearance from the upper and only touches the upper through the threads of the barrel nut. Link to comment Share on other sites More sharing options...
Shooter115 Posted February 4, 2015 Share Posted February 4, 2015 Nobody has mentioned the Nordic handguard yet. Everything you need, nothing you don't and it's less than $100. If you want to hang light's, laser's, espresso machines, ect off your rifle. I really like the one from APF Armory. Link to comment Share on other sites More sharing options...
BOOM Posted February 4, 2015 Share Posted February 4, 2015 THANKS Kurtm; got it the two should not be dead tight. Yea Shooter115; the Nordic is priced right not sure WHY not seeing more of them , also liking MI keymod Link to comment Share on other sites More sharing options...
Dewberry Posted February 4, 2015 Author Share Posted February 4, 2015 Well I went with the SLR ultra light. I'll let y'all know how I like it when it shows up. What length, and with what length barrel? 16.5" I plan on using a rainier 18" match spr Link to comment Share on other sites More sharing options...
WCK Posted February 5, 2015 Share Posted February 5, 2015 The Nordic handguard is nice for the price, but they are a heavy handguard. Link to comment Share on other sites More sharing options...
Dewberry Posted February 5, 2015 Author Share Posted February 5, 2015 I've never used the Nordic, but I've had another brand with the same barrel but design. And I hated it, hard to square and kept walking off. Link to comment Share on other sites More sharing options...
Vlad Posted February 5, 2015 Share Posted February 5, 2015 I've never used the Nordic, but I've had another brand with the same barrel but design. And I hated it, hard to square and kept walking off. I'm forced to agree, it looks identical to the YHM ones (heck it might be a YHM one) and that was nothing but trouble in my experience. Link to comment Share on other sites More sharing options...
Langenator Posted February 5, 2015 Share Posted February 5, 2015 Nobody has mentioned the Nordic handguard yet. Everything you need, nothing you don't and it's less than $100. When I click on the links to get to the detail view of the handguards (both NC-1 and NC-2) on Nordic's website, I get a 404. Link to comment Share on other sites More sharing options...
BOOM Posted February 7, 2015 Share Posted February 7, 2015 AP carbon fiber handguard looks pretty nice it covers the bottom, and the M style holes along the top lets some air in. How sturdy do these feel going out to 15"., and is there's some sorta anti rotation device built into AP handguard. Also does this come with a barrel nut. Link to comment Share on other sites More sharing options...
aquaticvisions Posted February 7, 2015 Share Posted February 7, 2015 Realize that when holes or slots are drilled into carbon fiber it weakens the overall structure. Strength comes from CONTINUOUS fibers. Link to comment Share on other sites More sharing options...
Vlad Posted February 7, 2015 Share Posted February 7, 2015 Holes in everything do that, aluminum included. My AP handguard does not feel flimsy at all At 15" it does flex a bit, at 13" it feels more rigid. The hadnguard is screwed to the barrel nut trunion (which uses the factory barrel nut) so it can't rotate. Link to comment Share on other sites More sharing options...
BOOM Posted February 7, 2015 Share Posted February 7, 2015 Thanks for sharing; Is there a 15" tube that's very rigid with (no Flex) Running the Key Mod,or M slots all the way down the tube must be a way of reducing weight. Link to comment Share on other sites More sharing options...
Vlad Posted February 7, 2015 Share Posted February 7, 2015 To be fair, AP just released their new Gen II tube with a better mounting system, an end cap and maybe a top rail if you want it. That would probably be more rigid. I'm not sure you can get a no flex tube, even aluminium flexes a bit. Link to comment Share on other sites More sharing options...
Steve RA Posted February 7, 2015 Share Posted February 7, 2015 It really doesn't matter if it flexes a little bit, as long as it doesn't touch anything (except at the mounting point) there is no problem. Link to comment Share on other sites More sharing options...
LikesToShoot Posted February 8, 2015 Share Posted February 8, 2015 Thanks for sharing; Is there a 15" tube that's very rigid with (no Flex) Running the Key Mod,or M slots all the way down the tube must be a way of reducing weight. You might want to look at the APcustomUSA.com Rhino series. While it weighs more than their Ultra Light and new Gen II ultra light it does offer the extra rigidity and flat surfaces that some may like. I wanted access to the gas block adjuster and Aaron said they could provide an access hole if needed. He agreed that my use of a high speed dremmel, with the correct bit, should be fine. Worked for me. Link to comment Share on other sites More sharing options...
CyclicRate Posted February 9, 2015 Share Posted February 9, 2015 (edited) I can't recommend the Midwest Industries lightweight rails enough. They have keymod and m-lok styles. My 15" m-lok weighs 9.3oz. That weight includes everything needed for installation (barrel nut, hardware, etc.). On top of everything, they're extremely well made and very affordable. Edited February 9, 2015 by CyclicRate Link to comment Share on other sites More sharing options...
jon49erfan Posted February 9, 2015 Share Posted February 9, 2015 My only problem with the MI is the small diameter. great rails otherwise. Link to comment Share on other sites More sharing options...
CyclicRate Posted February 9, 2015 Share Posted February 9, 2015 (edited) I felt that way about the naked KMR, but the MI with Magpul M-Lok covers fits my hand perfectly. Edited February 9, 2015 by CyclicRate Link to comment Share on other sites More sharing options...
michael1778 Posted February 9, 2015 Share Posted February 9, 2015 Realize that when holes or slots are drilled into carbon fiber it weakens the overall structure. Strength comes from CONTINUOUS fibers. Holes in everything do that, aluminum included. My AP handguard does not feel flimsy at all At 15" it does flex a bit, at 13" it feels more rigid. The hadnguard is screwed to the barrel nut trunion (which uses the factory barrel nut) so it can't rotate. OK, I will try to contribute to the material science and mechanics of materials portion of this thread. I'm doing composite material research in graduate school anyway, so I might as well use that for the common good. :-) Both of my BE.com friends quoted above are correct about discontinuous fibers and "holes" in things. However, for fiber reinforced plastics it's worse than you think when you apply concepts from metal behavior. I have an AP Customs carbon fiber handguard on my current competition rifle. I think it has two concerns. One, the mounting on the mil-spec barrel nut isn't as stiff as some of us would like (not a material issue). Two, the "holes" in the carbon fiber have a significant impact (large decrease) on the stiffness of the material (the discontinuous fiber idea) as well as induce large stress concentrations; much more than in metallic materials ("holes" idea). When you compare to a CF tube with continuous fibers, like the Carbon Arms model I have on another rifle, it's a noticeable difference in material properties. When you put that many slots into a handguard, you're getting mostly the matrix (a.k.a., plastic) as the driver of stiffness. The fibers have to transfer load into the matrix all over the place and can't use their native properties very well. Then you get the stress concentrations from the openings ("holes"). So many people hear about the stress concentration factor of a circular hole in a plate being "3x" when they take a basic materials class. Many come away with the idea that it was driven only by geometry. Unfortunately, that is not the case. It a function of geometry as well as the small scale material properties. Carbon fiber (CF) reinforced plastics can have nearly 9x stress concentration factor for the same geometry that gives you 3x in an isotropic metal. Sometimes the superior properties of the CF composite can naturally overcome that. But if you put a bunch of slots in a handguard, I'm not so sure. My engineering brain has grown much more doubtful over time. I'm running a bipod now and may have need for one or two other options on the handguard, so I expect that a more traditional metallic design with many attachment options will be in my future. Comparing to other CF handguard designs on the market: PRI doesn't do as many "holes" and makes them circles, not long slots. I think that is on purpose. That gives a smaller fraction of cut fibers while using a more benign shape for the "holes". Similarly, the weight of the Lancer models tells me that they have thickened the tube laminate enough to overcome the slots they have put in. But, that often means that the weight savings over isotropic metal designs is reduced. As an example of a very recent design, BCM claims to use a aluminum-magnesium alloy for part of their weight reduction. Then the 1.3" inner diameter geometry helps reduce the total amount of material needed (my observation, not their claim). That should be smaller than the I.D. of my AP Customs handguard. That seems like one part modern metallurgy and one part geometry "cheating" (in a good sense.) So, I've rambled. My intent was to highlight what are the issues involved with carbon fiber in handguards. In my personal opinion, it's no accident that CarbonArms focused their handguards on continuous fibers. The stiffness and strength (these are not the same properties) are both preserved that way. I love composite materials, so much so that I've dedicated my PhD research to their use in high performance spacecraft applications, not to mention my past engineering work designing nuclear submarine structures with FRP. But, even with my love affair for fiber reinforced plastics (FRP), one needs to be careful in their application and use. To that end, any handguard that I need which will have lots of 'stuff' on it, I'll very likely go with something metallic. For clean-lined competition uppers with no "go-faster" parts for Open/Unlimited, I would strongly consider a continuous fiber CF handguard or a CF model that showed clear evidence of over-design to counteract problems (e.g., added material, etc) caused by discontinuous fiber reinforcement and stress concentrations. If you made it this far, I sincerely thank you for reading. Link to comment Share on other sites More sharing options...
Vlad Posted February 9, 2015 Share Posted February 9, 2015 The question is though .. How many handguards are people breaking? Without a doubt putting holes in things makes things weaker, but do we care as long as a threshold isn't passed? I think the biggest problem with the AP handguard is the narrow mounting trunion and the 3 screws holding it. I think a lot of the perceived flex was from that area. The Gen 2 with the more mounting surface might solve that. That said, I like my AP hanguard and haven't snapped in half yet. Link to comment Share on other sites More sharing options...
michael1778 Posted February 9, 2015 Share Posted February 9, 2015 The question is though .. How many handguards are people breaking? Without a doubt putting holes in things makes things weaker, but do we care as long as a threshold isn't passed? I think the biggest problem with the AP handguard is the narrow mounting trunion and the 3 screws holding it. I think a lot of the perceived flex was from that area. The Gen 2 with the more mounting surface might solve that. That said, I like my AP hanguard and haven't snapped in half yet. That is the key question, I agree. I haven't seen any complaint about a breakage. I'm not that connected with the larger community either, but one would think we would see lots of complaints if it were a significant issue in the real world. I did want to lay out the relevant composite material issues for all to see. That was my main goal. And yes, I am in strong agreement that the movement many of us notice is most likely from the mounting system in the first generation product. That is the case for my handguard, at the very least. As such, I'll replace it with something else this year. At the moment, I have to decide what this rifle will be used for in the future. It may get rebarreled for a different purpose than typical 3-gun work which may mean a new role for the handguard. Link to comment Share on other sites More sharing options...
BOOM Posted February 9, 2015 Share Posted February 9, 2015 The addition of a 45 deg.front sight, and a sling attachment was the reason for asking about flex on a 15" tube. To me a Ridged tube trumps weight, but with all those slots not sure theres that much weight out front because of the handguard Link to comment Share on other sites More sharing options...
Vlad Posted February 10, 2015 Share Posted February 10, 2015 I would not put sights on a AP handguard, or at least not the gen1. Then again, I'm against putting any sights on any handguard so .. Link to comment Share on other sites More sharing options...
Nebwake Posted February 10, 2015 Share Posted February 10, 2015 Yea if you are breaking a hand guard, you need to go fight mma or something. Your rifle is a tool not a club. Link to comment Share on other sites More sharing options...
dauntedfuture Posted February 10, 2015 Share Posted February 10, 2015 (edited) My first 3g rifle wore a 12" larue hand guard. I suppose it was mostly because I did not exactly know more or better at the time. The Laure hand guards are great but they are heavy and if you are not going to mount anything on them, then its a little bit of a waste. I switched from that to a JP 12" and it was a marked improvement. I liked the rigid system, it is lighter, and a little less expensive. Shortly there after I switched the 12" out for a 15". All this time my rifle got heavier and heavier. With the 15" I made a hole in the side to adjust the gas block and added an AP QD button on the side. My new build will wear an AP CF handguard with an AP qd button on the side. I have not thought about a light option. If I was to do it over, and I might switch it out there are several good options from SLR and BCM. The Troy rails are another good slim option for the money. Provided its a free floating and rigid system I should think that you look at weight, girth and what if anything you want to attach to the rail. Edited February 10, 2015 by dauntedfuture Link to comment Share on other sites More sharing options...
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